(Not applicable)
(1) Field of the Invention
The present invention relates generally to apparatus for selecting random length materials, such as wood flooring stock and bundling nested combinations into a standard length, and more particularly to an improved apparatus for automated sorting of a plurality of random length stock into standard length combinations for bundling.
(2) Background Information
Solid wood flooring is typically produced in random lengths, which vary from nine inches to eight feet long. The length is determined by cuts made to remove randomly placed defects in the natural raw material.
The flooring stock is typically shipped in standard bundles ranging from seven to eight feet long, and therefore the flooring stock is conventionally bundled in one or two ways: (1) sorting by length to the nearest even foot in length, with various length bundles included on a single pallet; and (2) nesting various lengths of wood stock into a standard bundle, typically seven to eight feet long. In either case, the top layer of flooring in each bundle is inverted, so that the face of the product is protected from damage during shipping and handling.
Nesting is becoming the preferred method of bundling, because it is easier to handle and ship and typically assures a random assortment of lengths for the installer.
The most popular method for assembling random length wood flooring into nested bundles uses people to manually assemble the bundles. Generally, a person will first determine the grade of the flooring board by visual inspection. The inspected stock is then placed into a rack and sorted by its approximate length. A person on the other side of the rack will then remove selected pieces from one or more slots in the rack, visually judging the lengths to make a row of the desired standard length, when the pieces are nested end to end. In this method, the wood stock is generally sorted into approximate one foot increments. However, rarely are the boards exactly cut to the foot, and therefore are either longer or shorter than the increment slot in the rack in which it is placed. For this reason, once a combination of pieces is selected by the person assembling the bundle, it is often necessary to remove and replace various pieces to adjust the overall length of the nested row to fit the predetermined standard.
On the other hand, if the person grading the stock sorts the stock into racks with smaller increments, the sorting rack must necessarily be larger, and more time must be spent determining the proper slot in the rack for storage, as well as determining appropriate lengths for selection and nesting into the desired predetermined length row.
In some cases, a separate automated sorting mechanism is used to sort the wood stock by approximate length after grading. However, the nesting process is still currently accomplished manually by people. After enough rows of a proper length have been selected (usually twelve to fifteen rows for standard strip flooring) the top layer of product is manually inverted to protect the upper face of the product. The bundle is then tied together with plastic straps by a banding machine and the bundles are palletized for shipping.
As each row of nested lengths are assembled into a stack forming a bundle, each row is typically abutted flush, allowing the distal ends of the rows to vary. Thus, the bundle will typically include a proximal end with all rows abutted flush, and a distal end with a xe2x80x9cjaggedxe2x80x9d appearance because of the various completed lengths of rows.
In an alternative bundling method, each end of the pieces of material are abutted against stops, forming flush ends, with the gaps between nested pieces located in the middle of the bundle. Frequently, the interleaving of the pieces in this particular method is not adequate to hold the bundle together and the bundle is not as secure when bound. This method also makes it more difficult to estimate the total actual footage of the material in the bundle. Because the longest and shortest rows in the bundle are typically four to six inches longer or shorter than the predetermined average, longer pallets are necessary for shipping and storage.
In forming a xe2x80x9cjagged endxe2x80x9d bundle, the bundle assembler typically starts with a long piece of wood stock, or a combination of short pieces, and then chooses a short piece that will nest with the initial piece or pieces to approximate the desired predetermined length. This results in most of the short pieces being located at the jagged end of the bundle, which can then be easily dislodged from the bundle during handling and shipping. Frequently, when a truck or container of flooring is opened at its destination, dozens of short pieces of flooring have fallen from the bundles, with no way of determining which piece belongs to which bundle. This in turn results in a shortage of wood product from bundles, to the end user.
The process of assembling bundles is further complicated by the measuring rules commonly used in this industry. A standard machining or xe2x80x9cend matchingxe2x80x9d allowance of xc2xe inch is allowed on each piece of flooring. End matching is the process of putting a groove on one end of a piece of flooring stock and a tongue on the other end. The tongue and groove then interlock to prevent displacement of the ends of the flooring over time. The standard method of measurement for wood flooring calls for the addition of xc2xe inch to the length of the face of each piece, in order to allow for the material which is necessarily removed by the end matching process. This means that, if a row is being assembled for a standard length bundle, it may be xc2xe inch short if the row consists of one piece of wood stock, 1xc2xd inches short if made up of two pieces of wood stock, etc. In practice, the average length is assumed, and the target bundle length is shortened by the required amount.
Industry grading rules also require a minimum average length for each grade. The system of the present invention allows the processor to easily keep track of this information.
The current process of creating nested rows to form bundles by hand is time consuming, tedious, and proficiency requires consider experience. Some bundle assemblers never become good at choosing an acceptable combination of wood stock lengths on the first or second try, and therefore must spend additional time in a trial and error process to form a bundle. Further, the manual process of selecting rows for a bundle is not particularly accurate when assembled by hand, especially if the person assembling the bundle is in a hurry to create the bundle.
Further, once assembled, it is difficult to obtain an accurate measure of the material which is included in each bundle, especially if the method of forming the bundle with two flush ends is utilized.
It is therefore a general object of the present invention to provide an improved bundling apparatus for selecting random length pieces of product to form standard length bundles.
Another object is to provide a bundling apparatus which is automated to improve the accuracy of the overall length of rows within a bundle.
A further object of the present invention is to provide an automated bundling apparatus which is capable of documenting the length of pieces within a bundle more accurately than possible when assembled by hand.
Yet another object is to provide an automated bundling apparatus in which the number of pieces in a row of a bundle is automatically tracked, to automatically compensate for end matching allowance.
Still another object is to provide a bundling apparatus which is capable of tracking minimum average length information for each grade of product.
These and other objects of the present invention will be apparent to those skilled in the art.
The method and apparatus for selecting random length boards for nesting into a single row of predetermined lengths includes the initial step of arranging a plurality of random length boards on an accumulating rack. A plurality of the boards are then conveyed to channels in an adjacent storage rack. The length of each board is determined as the board is conveyed from the accumulating rack to the storage rack, and this information is transmitted to a central processor. The processor calculates combinations of board lengths in the storage rack which will form a single stock row having a combined board length within a predetermined target range. The processor then selects a preferred combination of boards from the possible combinations, and activates gates in the channels to drop the boards to a conveyor and move the selected boards to a stock row accumulating location. The processor then activates gates on the accumulating rack to convey additional boards to empty channels in the storage rack, and repeats the process. The apparatus includes an accumulating conveyor with longitudinal tracks positioned adjacent a storage rack with longitudinal channels aligned with the tracks. A scanning assembly is positioned between the accumulating conveyor and storage rack for scanning boards moving between the conveyor and storage rack, to determine the length of each board. The central processor is connected to the scanning assembly, and gates on the accumulating rack and storage rack, to automatically operate the system.